The present invention relates to communications systems and more particularly to communications systems which have adaptive06ignal processing. One established method of providing a communication system adaptive signal processing system with a reference signal is to transmit a pseudo random sequence with the information modulated on top of the sequence. This approach suffers from the disadvantage of requiring an entirely new modem for each application. Also for any given existing system, this approach would require extensive equipment changes. The processing gain in the reference generation loop is given by the ratio of the total bandwidth to the information bandwidth. This processing gain would be severely limited for existing systems because this modulation bandwidth (information rate) is a large percentage of the frequency assignment. In situations where jammers are used as, for example, in military application, a pilot tone could not be used as the reference signal since a jammer could also generate the same reference signal.